[From Bruce Abbott (941029.1600 EST)]
"Sparkin" Rick Marken (941028.1030) --
I (941020.2245) added the following:
And such an experimenter would object to being classed, along with
the forest people of New Guinea, as an "animist" (one who believes
that objects such as rocks and trees are alive and have souls) eventhough this is precisely what he (or she) is -- a "Skinnerian animist".
To which Bruce apparently took offense . . .
Rick, "offense" is too strong a term. "Mildly annoyed," perhaps, or even
"irritated," maybe, but not offended. No apology necessary. And pay no
attention to that surly mob with the torches and pitchforks you see
approaching in the distance...
Since you're a modeler, and also know authoritatively how reinforcement
is supposed to select behavior, perhaps you can come up with a
reinforcement simulation that will produce the E. coli effect. Perhaps
both Rick and I failed because we didn't find the right model. If you
could find such a model, that would be an important result, because it
would disprove what Rick and I thought the E. coli model proved: the
production of a systematic effect without any reinforcement as (we
thought) reinforcement is conceived.
Long ago Thorndike proposed the "Law of Effect," the Fundamental Theorem of
reinforcement theory. In it he defined his "satisfiers" (reinforcers) and
"annoyers" (punishers) thus:
By a satisfying state of affairs is meant one which the animal does
nothing to avoid, often doing such things as attain and preserve it. By
a discomforting or annoying state of affairs is meant one which the
animal commonly avoids and abandons. (Thorndike, 1911)
Given this, I could explain in reinforcement terms e. coli's success in
eventually reaching the source of nutrients by noting that the "reinforcement"
of increasing nutrient density keeps the critter moving in the same direction
until continued "responding" in that same direction begins to be "punished" by
a decrease in nutrient density. The punishment would then suppress the
response, causing e. coli to randomly select a new direction of travel. In
this way all behaviors leading to increased nutrient concentration continue to
be maintained, whereas those that lead to decreased concentration are soon
abandoned. Thus responses are selected by their consequences.
Getting back to the challenge:
Since you're a modeler, and also know authoritatively how reinforcement
is supposed to select behavior, perhaps you can come up with a
reinforcement simulation that will produce the E. coli effect. Perhaps
both Rick and I failed because we didn't find the right model.
The challenge is easily met. The program (in pseudo-code) is this:
repeat
inc(Clock);
If Going_up_gradient then continue;
If Going_down_gradient then tumble;
until Clock > EndSimulation
Happy Trails,
Bruce